Overall goals of this project are to define the nature of genes which code for, or otherwise affect the structure of immunoglobulins (Igs) and to understand the processes which regulate Ig-gene expression and lead to synthesis of highly specific antibody molecules. We prepare immunological reagents that detect structural differences between genetically controlled polymorphic forms of rabbit Igs (Ig allotypes). We use immunological, chemical and molecular genetic approaches to define the Ig-structural differences and to learn more about the chromosomal organization of Ig genes, the regulated expression of antibodies, and antigen-specific receptors on lymphocytes. Inheritance patterns and the levels of regulation of phenotypic expression of alleles and chain types are investigated by breeding experiments, by studies of ontogeny and differentiation of cells of the rabbit immune system and by direct molecular genetic analyses. We use recombinant DNA technology to examine genome organization by isolation of rabbit Ig genes and to prepare cDNA copies of Ig mRNA. Characterized DNA probes will permit us to identify and analyze Ig variable and constant region DNA sequences as well as adjacent sequences and to characterize nuclear RNA precursors and their processing steps in the production of Ig mRNA.